Guns
Guns are the primary armament of most ships. General Principles Guns range in size from 2" to 20", and in quality from -2 to +1. The size of a gun affects its range, penetration, damage, and the mass of its gun mount and ammunition. The quality of a gun affects range and penetration as well. As a rule of thumb, one quality level will increase range and penetration roughly as much as one inch of calibre, but without any weight increase. Flash Fires Guns may occasionally be the victim of flash fires, where an unlucky hit makes it to the gun's magazine, detonating it. This destroys the ship instantly. The mechanics on this are somewhat uncertain (see this thread, for example), but suspicion is that all main guns may flash-fire, and secondary guns either 6" and larger or 7" and larger. Many players prefer to use substantially more armour on guns above 6" calibre to avoid this effect. Great Britain has a national penalty that gives them increased vulnerability to flash fires as of the 1900 start date, to reflect their very high battlecruiser losses at Jutland (among others), so this is especially relevant for British designs. Every turret flash fire reduces the subsequent risks of flash fires, to represents improvements in safety procedures in light of disastrous explosions. Note this only applies to turret flash fires and does not affect magazine explosions from penetrated magazines. Turrets and Casemates Guns may be mounted in single-gun casemates or turrets of 1-4 guns. Casemates have limited fields of fire, and cannot be used with dual-purpose guns. They are also affected more strongly by rough weather, especially on ships with low freeboard. However, armour on casemates helps increase the effective armour of a ship's belt. Casemates are also somewhat lighter than single-gun turrets, and they do not consume topside space, allowing a ship to mount more light and medium anti-aircraft guns. Turrets have wider fields of fire than casemates. Turrets may mount dual-purpose guns, increased elevation, and cross-deck firing, with appropriate technology and layout. Turrets can also mount multiple guns at once, and receive weight savings when they do so. However, if a turret is disabled or destroyed, all guns in that turret are also knocked out. Turrets must also have armoured roofs if the turret is to be armoured, which can increase weight. In 1900, only casemates, single turrets, and dual turrets are available, and double turrets are only allowed on some ship classes. Triple and quadruple turrets are unlocked by technology, and even after they are unlocked they are less reliable than smaller turrets until the Improved Triple and Improved Quadruple technologies are unlocked. However, they allow more firepower in a more compact area, and help save weight. As well, turrets larger than double may never be mounted in wing positions. Main, Secondary, and Tertiary Guns Each ship class may have three different gun calibres - the main battery, secondary guns, and tertiary guns. The main battery can be customized significantly, with the player choosing how many guns to mount in which positions. The main battery also affects many things about the ship - it often helps determine the ship's class, and it is the only battery considered for whether a ship receives the weight reduction from all-forward armament, for example. Ammunition load per gun may also be customized, though every main-battery gun on a given ship gets the same ammunition load. Main battery guns may benefit from fire control bonuses from the beginning of the game. Main guns are typically armoured (except for ship classes which disallow armour, such as destroyers). Secondary guns may be used if main guns are mounted, and must be a smaller calibre than the main guns. Secondary guns may not be customized as aggressively as main guns - their positions are automatically chosen by the ship designer, and they are always symmetrical around the ship's centreline. (Note that not all secondary guns are always illustrated, especially if there are 2+ guns per turret. The remainder are placed on the ship's centreline.) Secondary guns may be armoured, and they may use directors once the appropriate technology has been unlocked. Tertiary guns may be used if secondary guns are mounted, and must be a smaller calibre than the secondary guns. Tertiary guns are not illustrated on the ship, and are again auto-placed symmetrically. Tertiary guns may not be armoured, and may not use directors. The mounting of tertiary guns does not affect their mass, unlike main and secondary guns. However, it does affect them for the purpose of making guns DP - casemates and triple/quad turrets cannot mount DP tertiary guns. (Unsure how it affects fields of fire or battle damage) Gun Enhancements Guns may be enhanced with certain additional features as technology advances. Dual-Purpose guns may fire on enemy aircraft - they are considered heavy anti-aircraft in a ship's statistics. Only guns of 3-6" may be true DP guns, and they must be mounted in single turrets or (when tech permits) double turrets. Mixing DP calibres is penalized, with all calibres but the largest receiving a 60% penalty to their effectiveness, due to the difficulty in determining which shells are doing what. Generally, 4" and 5" are the most effective calibres for anti-aircraft purposes. DP guns should be given a large amount of HE shells by the nation's doctrine, as HE shells are what is fired at aircraft. Dual-purpose guns weigh more than standard guns, but due to their increased flexibility, they are popular on ships designed after roughly WW1. Auto-Loading '''guns have improved rate of fire compared to their regular counterparts. ROF is increased 10% in most circumstances, and 30% when the gun is on target and making hits. Auto-loaders are available for guns of 3"-8", and are popular for post-WW2 era designs. Again, there is a weight penalty for auto-loading guns. '''Increased Elevation on guns increase the range of the guns. This has no weight cost, but requires a refit to retroactively apply to older ships.. Cross-Deck Firing may be used for guns mounted in wing positions. It improves their firing arc, giving them a narrow arc on the opposite side of the ship from where they are mounted - for example, a port-mounted turret may fire to starboard. It has a minor weight penalty, note this is not applied to the turret's weight. Statistics Gun statistics for various calibres are given below. These values are all raw numbers, and the units are not specified. Many multipliers are applied by the game engine that will not be included below. As a result, these numbers can be used to compare different guns to each other (assuming the same tech and quality levels), but they should not be expected to match any values given in-game. Range/Rate of Fire/Damage Gun statistics as of v1.05b, taken from this thread and this thread. Minimum ship mass refers to the size a ship should be to avoid a 20% rate of fire penalty for being over-gunned. Damage is based on shell mass to the power of 2/3, per a dev post in the linked threads. Base penetration of vertical armor Penetration values can vary up to 20% to simulate the presence of weak spots in the armor. Range (kyd) Calibre 4" 5" 6" 7" 8" 9" 10" 11" 12" 13" 14" 15" 16" 17" 18" 19" 20" 1 60 80 100 120 160 160 160 200 240 260 280 300 320 340 360 380 400 2 55 80 100 120 160 160 160 200 240 260 280 300 320 320 340 360 380 3 52 80 100 120 150 160 160 198 240 260 280 300 320 320 330 340 360 4 50 70 90 110 140 150 155 195 220 260 270 290 320 320 330 340 350 5 40 60 80 100 130 140 142 190 210 240 260 280 300 320 320 330 340 6 30 52 70 90 120 130 130 180 200 220 240 260 280 300 320 330 340 7 26 46 60 80 110 120 120 160 180 210 230 250 270 280 300 320 330 8 24 40 52 70 100 110 113 153 170 200 220 240 260 270 280 300 310 9 20 32 46 60 93 100 107 147 160 190 210 220 250 260 270 280 290 10 28 40 55 87 93 100 140 150 180 200 210 240 250 260 270 280 11 24 36 50 80 87 93 128 140 170 190 200 220 240 250 260 270 12 20 32 45 73 80 87 118 133 160 180 190 210 220 240 250 260 13 28 40 67 73 80 112 127 150 170 180 200 210 220 230 240 14 24 36 60 67 75 104 120 140 160 173 193 200 205 210 220 15 20 33 57 60 70 98 113 133 153 167 187 193 200 205 210 16 30 53 56 65 91 107 127 147 160 180 187 193 200 205 17 26 50 52 60 84 100 120 140 153 170 180 187 190 197 18 23 47 48 56 78 93 113 133 147 160 170 180 186 192 19 20 43 44 52 74 87 107 127 140 153 160 170 180 188 20 40 40 48 70 80 100 120 133 147 153 160 168 176 21 36 36 44 65 76 96 115 127 140 147 153 162 170 22 32 32 40 61 72 92 110 120 135 140 147 152 160 23 28 28 36 58 68 88 105 115 130 135 140 144 148 24 24 24 32 54 64 84 100 110 125 130 135 138 143 25 20 20 28 48 60 80 96 105 120 125 130 134 138 26 24 44 55 76 92 100 115 120 125 130 134 27 20 40 50 72 88 95 110 115 120 124 128 28 36 45 68 84 90 105 110 115 118 121 29 32 40 64 80 85 100 105 110 112 115 30 28 35 60 76 80 95 100 105 110 112 Base penetration of horizontal armor Range (kyd) Calibre 4" 5" 6" 7" 8" 9" 10" 11" 12" 13" 14" 15" 16" 17" 18" 19" 20" 6 10 10 10 10 7 10 10 10 10 12 12 12 12 8 10 10 10 12 12 12 12 15 15 15 16 9 10 12 12 12 14 14 15 15 17 17 18 19 10 10 11 14 14 14 16 16 17 17 20 20 21 22 11 10 11 12 15 15 16 18 18 20 20 22 22 23 24 12 10 10 10 12 12 13 16 16 18 20 20 22 22 24 25 25 26 13 11 10 12 14 14 14 18 18 20 22 22 25 25 26 27 27 28 14 12 13 15 16 16 16 20 20 22 24 25 27 27 29 29 30 30 15 13 16 17 18 18 18 22 22 24 26 27 30 30 31 32 33 35 16 14 18 19 19 20 21 23 24 25 28 30 32 32 35 37 40 42 17 15 22 22 23 20 23 24 26 26 30 32 34 35 38 40 42 44 18 15 22 23 26 22 26 27 28 28 32 34 36 38 40 42 44 46 19 15 22 23 24 25 28 30 30 30 35 36 38 40 42 44 47 50 20 15 22 27 27 27 32 32 33 33 37 38 40 42 45 48 50 54 21 15 22 30 32 32 36 36 36 36 40 40 43 45 48 50 54 58 22 15 22 32 35 35 40 40 40 40 43 43 47 48 50 55 60 64 23 15 22 32 42 40 45 45 45 45 47 47 50 50 55 60 64 68 24 16 22 32 42 45 45 45 45 50 50 50 55 55 60 64 68 72 25 16 22 32 42 50 50 50 50 55 55 55 60 60 65 68 70 72 26 16 22 32 42 50 50 50 55 58 60 60 63 65 70 70 72 74 27 16 22 32 42 50 50 50 58 60 60 63 67 70 70 70 72 74 28 16 22 32 42 50 52 50 60 60 60 67 70 70 72 72 74 76 29 16 22 32 42 50 52 52 60 60 60 70 70 72 72 74 76 78 30 16 22 32 42 50 52 52 60 60 60 70 72 74 74 76 78 80